Atom Packs The Mo 50L Pack Review

Joal and I have struggled to find gear made in the UK for the thru-hiking community so we were super excited when a friend recommended we check out Atom Packs, a UK-based company that makes custom ultralight backpacks. This hiking season I’ve been testing their 50L Mo.

Who are Atom Packs?

Meet Atom Packs, a cottage pack company based in the Lake District in the UK. The company was founded by the triple crowner Tom Gale, a professional mountain leader with over 12,000 miles under his feet. The custom gear company has built itself a great reputation over the last few years for lightweight, long-distance hiking packs which are competing for the top spot among the leading brands on the trail today.

The journey started, as many cottage light-weight pack companies do, with the personal quest for a lighter bag.  Following an encounter with a fellow thru-hiker on the Te Araroa, Tom borrowed a friend’s sewing machine and emerged with a self-proclaimed “monster” of a pack.  After learning the downsides of going stupid light, Tom honed and refined the designs to the now six-strong lineup of bags offered through the site today. Tom and his team of five hand-make all the bags, and you can see the level of care and enthusiasm in the quality of the packs.

What makes Atom Packs special?

Buying a pack from Atom Packs is a different experience than going into your local REI and buying something off the rack. Tom is 6’7” and found he could not get a bag to fit him properly. I’ve struggled with as well as a petite female who doesn’t want to buy a child’s pack. With Atom Packs you’ll get a made-to-measure pack with customizable options galore. You can even ask for a bespoke pocket to carry your avocados safely! The whole process feels great. You’re at the heart of it and as a result, you’ll end up with a pack that is tuned to your desires.

The Products

Atom Packs has six main products alongside a number of accessories. Customizations are available for all of the below:

  • The Atom+: This is their most versatile pack. It’s lightweight enough for a weekender, yet robust enough to take on a thru. Weight starts at 20.5oz and is available in 40L and 50L versions.
  • The Mo: A framed, fully-featured pack that you can trust to carry you and all your gear on a thru. This pack goes up to 60L in volume and starts at 28oz for the 40L version.
  • The Atom: A minimalist backpack aimed squarely at those who want to travel fast and light. No hip belt. Available in 30L – 40L with a max load capacity of 20lbs. Starts at 13.4oz.
  • The Pinnacle: A minimalist climbing pack. Available in 30 and 40 liters and starts at 24.7 ounces.
  • The Nanu: A lightweight 25L non-technical daypack.
  • The Roo: Fanny pack available in 1.5 and 2.5L. Can be customized to match your pack

Gear Highlight: The Mo 50L

Atom Packs The Mo 50L custom pack.

Atom Packs The Mo At-a-Glance:

  • Volume: 40 – 60L. We are reviewing the 50L pack. This has an internal volume of 45L and 5L in external pockets.
  • Weight: Starts at 28.2oz (800g). Mine was 29.7 ounces (845g) with an S torso, two shoulder pockets, an additional bottom pocket, and two hip belt pockets. The two removable hip belt pockets add an additional ounce each.
  • Fabric options: VX07, VX21, LS21, 210D Robic Extreema. The pack we reviewed was made completely from 210D Robic Extreema.
  • Cost: £257 ($335 dollars at the time of this review) for the 50L model. £245 for the 40L and £269 for the 60L. Additional customizations are priced as per the website.
  • Suggested maximum carrying capacity: 40lb (18kg)
  • External pockets: Two large side pockets, an elastic Dyneema front pocket &bottom pocket, dual stretchy shoulder pockets, and two removable hip belt pockets.
  • Elastic compression straps: Zig-zag compression straps down the side and front of the pack and across the side pockets.

Conditions of Review

I had originally planned to test this pack on my 300-mile thru-hike of the Trans-Caucasian Trail through Armenia, but 2020 hasn’t quite turned out as planned. Instead, it has been worn on a week-long backpacking trip along the South West Coast Path and numerous multi-day hikes across the South Downs, Peak District, and Dartmoor.

The pack has over 300 miles under its belt. It has experienced a mixture of sweaty high-noon hiking, driving rain, and blustery days. We have tested the pack’s ability to cope with both speed hiking and multi-day heavy food carries. We deliberately filled it to its recommended capacity (40lb) for a three-night wild camping trip in Dartmoor. I also wore it on a weekender where we challenged ourselves to complete the Serpent Trail, a 75-mile hike through the South Downs, in two days.

The Mo Features

Dyneema stretch front pocket: This can hold a surprising amount of volume, I’d estimate 3-4L. I used this pocket numerous times every day to store layers I’d stripped off. It easily holds my rain jacket, puffy coat, leggings, and fleece, with additional space for our Sawyer Squeeze, sun cream, snacks, and battery pack.

Two 2.5L side pockets: These pockets are brilliant for long water carries. Each can hold 2 x 1L water bottles. I loved the ability to tighten the elastic cords to secure every hiker’s most precious commodity. This allowed me to bend forward and pick items up of the off floor without needing to worry about a bottle falling out and rolling down-trail–a nightmare situation in drier stretches of the trail!

Load lifters: These are essential for balancing a heavy load and directing the pack’s weight as close to your body as possible. On heavier carries the pack’s weight sat comfortably on my hips and moved in line with my body, leaving my shoulders feeling fresh and ready for the following day.

Removable back panel with aluminum stay: The plastic back panel and aluminum stay can be removed easily. I’ve tested taking this out and putting it back in again and it’s a simple process. Considering this pack is built to carry heavy loads, I’ve always hiked with it in, as it increases the comfort and carrying capacity of the pack. However, it’s nice to know that it can be removed for a lighter adventure.

Lumbar pad: This is the comfiest pack I have ever hiked with. I think a lot of this is due to this little beauty. The lumber pad sits snug in the small of your back, keeping the weight of the pack on your hips.

Roll-top and Y strap: I love the roll-top as it allows the bag to be filled to capacity on the first day out of town. When your food supplies begin to shrink the pack can roll down to match. The roll-top is secured with two sturdy side clasps. There is an additional Y strap on the top of the pack that enables a bear canister or other bulky loads to be stored on top of the pack, increasing the pack’s carrying volume substantially.


atom packs the mo

Comfort: This pack carries weight very comfortably. I was surprised by how great it felt when filled to capacity. I would attribute this to the pack’s carefully thought-through design. The pack directs the weight down onto your hips through the use of the load lifters and elastic cording that can be cinched tight to keep the pack condensed. This makes a heavy load feel lighter. The adjustable sternum strap, hip belt, and lumbar pad hold the weight snug to your body. Usually, on longer hikes, I experience hip sores or rubbing on my lower back. So far I haven’t experienced this with the Mo, making this the comfiest backpacking pack I have ever worn.

While we were reviewing the pack Tom reached out as he was experimenting with straps more fitting for a female hiker. These new straps are great. They further increase the comfort of the pack and the additional more rigid padding on the shoulder straps will become a standard feature of new packs.

Customization: Tom and the gang at Atom Packs can accommodate all sorts of customization in terms of aesthetics (they have an impressive range of colorful fabrics and cording) and functionality. I admit I did go a bit over-the-top on my feature customization, as I asked for two removable hip pockets, two shoulder pockets, and a bottom pocket. I am in love with the bottom pocket. It’s a lot easier to access than twisting your arm around to reach the front stretch pocket. It’s made from Dyneema stretch fabric, which adds to the durability of the pack against abrasion when set down. I used it to store smaller layers I had stripped off, my face mask (so totally 2020), and empty snack packaging.

The pack really does feel bespoke to me, my hiking style, and my body. On reflection, I would recommend getting the bottom pocket and a single shoulder pocket for your phone but I’m not sure I need six big pockets within reach while hiking. My suggestion would be to use the pack without hipbelt pockets and if you need more storage these can be added later as these are removable.

atom packs the mo
Volume to Weight Ratio: This pack is 12.7 ounces lighter than my previous pack, yet it feels much better when carrying a heavier load as the weight sits snug to my back. The minimalist interior, generous roll-top, Y strap, and removable hip belt pockets mean I can overpack the Mo when I need to, whether that means strapping a bear can to the top or packing a few beers to celebrate a milestone on the trail.


Breathability: The drawback of centering the pack’s gravity close to your body is that there aren’t any gaps between your back and the pack for airflow. I was spoiled by the breathability on my last thru-hiking pack (the Osprey Exos). With the Mo, my back was sweatier on hot days than I am used to. This seems to be a common drawback of a lot of the lighter weight packs. They are either frameless or the frame molds to the wearer’s back instead of sitting against it. It’s a trade-off between carrying the weight smarter, increasing the overall comfort, or creating airflow.

atom packs the mo

Waterproofing: This pack is not waterproof, even when choosing a waterproof material like VPAC for the main body. This is because Atom Packs don’t offer seam sealing. This isn’t unique to Atom Packs, but you will need to take into consideration buying a waterproof stuff sack or bag liner. We’re used to not having waterproof packs so this wasn’t too much of an issue for us.

The Verdict

atom packs the mo

The Atom Packs The Mo has been a game-changer for me. It is both the comfiest and the lightest pack I’ve ever used on an overnight backpacking trip. I’ve enjoyed ultralight packs for smaller trips in the past, but I never thought I’d use one for a thru as I’ve never been keen to sacrifice comfort. The Mo proves that with a well-thought-through design, padding where it really matters, and efficient weight distribution, there is no reason ultralight can’t be ultra-comfy. The pack is an all-rounder. I’d recommend it to first-timers and seasoned hikers, over-packers, and ultra-lighters.

Shop the Atom Packs The Mo

Comparable Packs

Hyperlite Mountain Gear 3400 Southwest

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  • Weight: 32oz
  • Carrying capacity: 55L
  • Maximum suggested load: 40lbs

Mountain Laurel Designs Prophet

  • MSRP:$230
  • Weight: 17oz
  • Carrying capacity: 48L
  • Maximum suggested load: 25lb

ULA Circuit

  • MSRP: $255
  • Weight: 41oz
  • Carrying capacity: 68L
  • Maximum suggested load: 35lb

This pack was donated for the purpose of review.

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Comments 3

  • JOHN CRAFTON : Dec 3rd

    Thank you for the incredibly detailed review of the Inov-8 Terra Ultra 270 G. I’m retiring in a few years and hoping to do an AT Thru-Hike and the heavy old Hanwags just aren’t getting it done so I’ve been revamping my gear this year. I had a size 13 shipped in from Amazon and while the big toe length was fine the next two toes were not due to the shape of the toe box. I wish I would have seen your review sooner but it was the only one to mention sizing up. Anyway, thanks for the great review and best wishes!

  • Neet and Angel : Mar 18th

    Great review! I’m considering purchasing the Atom Pack 50L for my upcoming hiking trip. Could you elaborate more on the durability of the pack? How does it hold up in wet conditions?


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